The molecular logic of life. The biomolecules and water: the weak interactions in an aqueous environment. The amino acids and the peptide bond. The three-dimensional structure of proteins: secondary structure, tertiary and quaternary. Folding and denaturation of proteins. Outline of the main techniques of studying proteins. Relationship between structure and function of proteins: hemoglobin and myoglobin, collagen, keratin. Enzymes: classification, mechanism of action and Michaelis-Menten equation. Regulation of enzyme activity: activation and inhibition and role in the metabolism of regulatory enzymes. Carbohydrates and Lipids. Transduction and energy conservation: principles of bioenergetics. The redox reactions of biochemical interest. Basic concepts of metabolism: glycolysis and gluconeogensis, glycogen metabolism, citric acid cycle, oxidative phosphorylation, lipids metabolism. Metabolism of nitrogen compounds. Cellular communication.